A device that combined the functions of telephone and television; a phone with a screen.

This is a very early reference to this idea.

His physical superiority, however, was as nothing compared to his gigantic mind. He was Ralph 124C 41+, one of the greatest living scientists and one of ten men on the whole planet earth permitted to use the Plus sign after his name. Stepping to the Telephot on the side of the wall, he pressed a group of buttons and in a few minutes the faceplate of the Telephot became luminous, revealing the face of a clean-shaven man about thirty, a pleasant but serious face.

As soon as he recognized the face of Ralph in his own Telephot, he smiled and said, "Hello, Ralph." "Hello, Edward. I wanted to ask you if you could come over to the laboratory tomorrow morning. I have something unusually interesting to show you. Look!"

He stepped to one side of his instrument so that his friend could see the apparatus on the table about ten feet from the Telephot faceplate.

Edward came closer to his own faceplate, in order that he might see further into the laboratory.

This technovelgy item has been accomplished many times over the years; today's version of teleconferencing over the Internet via webcams is just the latest version. Curiously, it has never really caught on with the public; I wonder if people really want to be seen.

Take a look at this representation of the Telephot on an early cover for the novel.